Teleprinter having insignia forming matrices carried by a drum

ABSTRACT

Known high speed teleprinters are, in effect, signal actuated typewriters, and have the defect of being relatively slow speed. In the present invention a teleprinter includes letter or other insignia forming matrices composed of several mutually insulated elements, in such an array that different combinations of elements correspond to different letters, each element being an electrode of a condenser. Input signals cause different combinations of elements to be charged. A printing material is applied to the matrices, and the charged elements will electrostatically retain it, until the matrix is pressed against specially treated paper, to which the printing material adheres.

United States Patent TELEPRINTER HAVING INSIGNIA FORMING MATRICES CARRIED BY A DRUM 7 Claims, 5 Drawing Figs.

US. Cl 178/30 Int. Cl 11041 15/34, H041 21/04 Field of Search 178/30, 15

(Cursory) [56] References Cited UNITED STATES PATENTS 2,951,121 8/1960 Conrad 178/30 3,289,209 11/1966 Schwertz et a1 178/30 Primary Examiner- Kathleen H. Claffy Assistant ExaminerThomas W. Brown Attorney-Baldwin, Wight, & Brown ABSTRACT: Known high speed teleprinters are, in effect, signal actuated typewriters, and have the defect of being relatively slow speed. In the present invention a teleprinter includes letter or other insignia forming matrices composed of several mutually insulated elements, in such an array that different combinations of elements correspond to different letters, each element being an electrode of a condenser. Input signals cause different combinations of elements to be charged. A printing material is applied to the matrices, and the charged elements will electrostatically retain it, until the matrix is pressed against specially treated paper, to which the printing material adheres.

PATENTED rfiBzaisn SHEET 1 OF 3 INVENT R 3W WM 48 ATTORNEYS PATENTEU FEH23 I97! 3; 566; 030

sum 2 or s INVENTOR Maw/Wm & 6W1,

ATTORNEYS TELEPRINTER HAVING INSIGNIA FORMING MATRIEES CARRIED BY A DRUM This invention relates to teleprinters and, though not limited to its application thereto, is particularly well suited to high speed tcleprinters for printing lettered and like information from coded signals, e.g., the output signals from a computer.

One usual arrangement for printing the output data from a computer decodes the computer output signals and uses the decoded signals to control a printing machine of the electromechanical teleprinter type, i.e., what is in effect a signal actuated typewriter. Such an arrangement has the defect of being of relatively slow speed, the maximum rate at which the teleprinter can print the information being considerably slower than the rate at which the computer can provide the output data signals.

The present invention seeks to provide a teleprinter capable of high speed printing.

According to this invention a teleprinter comprises letter and other insignia forming matrices composed of a plurality of mutually insulated insignia elements each of which constitutes an electrode of a condenser, said elements being in such physical relationships that different combinations of the elements of a matrix correspond to different letters or other insignia; means operable by different combinations of input electrical signals for selecting different combinations of elements and charging the condensers of which these elements are electrodes; means for applying printing material to the elements whereby those forming electrodes of charged condensers will electrostatically retain said material; and means for utilizing the elements for printing after application of the printin material thereto.

Preferably the matrices are constituted by elements in predetermined physical relationship and which are carried by and insulated from a drum.

In a preferred arrangement there is a large number of matrices spaced from one another along spaced parallel lines running parallel to the drum axis. A preferred way of making a matrix is by means of a photographic and etching technique commonly used in the manufacture of printed circuits and known per se.

One embodiment of a teleprinter in accordance with the invention comprises a line of matrices, means for selecting in each matrix in turn a desired selection of elements representing a desired character or pattern to be printed, means for electrostatically charging said selections whereby they may electrostatically attract a printing material and means for transferring the printing material on said selection of elements to the surface to be printed.

Preferably there is a plurality of lines of matrices.

Preferably selection and charging of elements in one line is performed while selection and charging is still being performed in a preceding line of matrices.

Preferably signals for selecting elements to be charged are fed to the printer via a photoelectric link. The photoelectric link may include photosensitive diodes which are energized by light sources, for example gallium arsenide diodes, which emit light on the application of a suitable potential.

One form of printer in accordance with the invention includes a plurality of lines of matrices each arranged on the surface of a cylindrical drum and parallel to the drum axis, first switch means for selecting a desired selection of elements corresponding to a representation of the character or a pattern to be printed, second switch means for each of said matrices and in series with said first switch means whereby a desired selection of elements in a desired matrix may be connected to one pole of a source of charging potential, the other pole of said source being connected to a supply of printing material, means for rotating said drum, means for pressing the surface to be printed into contact with said drum, a photoelectric link for feeding into said drum signals according to the character or characters or patterns to be printed, and means for connecting said one pole of said source of charging potential to said switch means.

Preferably there is provided means for discharging the charged elements after the printing material has been transferred to the surface to be printed.

Preferably said discharge means comprises a conductive roller connected to earth adapted and arranged to contact the matrices on the drum after printing.

" The said printing material may comprise a suitable type of powder as used in copying machines working on an electrostatic principle.

The invention-is further described and illustrated in the accompanying drawings in which:

FIG. I shows schematically one form of printing device in.

accordance with the present invention;

FIG. 2 shows a simplified form of the device shown in'FlG. l;

FIG. 3 is a perspective view of part of a practical realization of the present invention as a high speed teleprinter;

FIG. 4 is a schematic representation of a teleprinter in accordance with the invention;

FIG. 5 is a circuit diagram of part of the logic circuitry used in carrying out the invention.

Referring now to FIG. 1, a printing device comprises a matrix of conductive and mutually insulated elements E1, E2, Ell-E14 supported on an insulating material I. The device may conveniently be made by a photographic and etching method known per se, such as for example as is commonly used in the manufacture of printed circuits. An inspection of FIG. 1 will show that by selecting an appropriate combination of the elements E1--El4 a representation of any capital letter of the alphabet or a representation of any figure 0-9 may be formed. By charging the selected combination of elements to an appropriate potential so that the said combination attracts a suitable printing medium, for example powder of the type commonly used in electrostatic copying machines, the device may be used to print a representation of a desired character by pressing it into contact with ordinary paper which may, if necessary, be moistened slightly or provided with a slightly tacky surface. Each of the elements El-El4 is provided with an electrical connecting wire so that it may be charged upon application of a suitable potential to the wire. The connecting wire connects to the lower surface of the element, i.e., the surface in contact with the insulator, and leads out through the insulator to a voltage supply (not shown). Wires are also not shown in FIG. 1 in order to preserve clarity. As an example, suppose it is desired to print a representation of a capital M. Elements E2, E3, E4, E5, E9 and E10 are charged up to attract printing powder and the device is then pressed into contact with a piece of paper to transfer the powder from the charged elements thereto. A representation of a D would be formed by charging elements E1, E2, E3, E4, E5, E6 and E14. A figure 2 would be formed by charging elements El, E3, E4, E6, E7 and E8 and so on.

If it is required to print figures only, i.e., 0-9, a simplified matrix of elements may be used and such a matrix is shown in FIG. 2. FIG. 2 is otherwise similar to FIG. 1 and no further description is required.

The matrices of elements in FIGS. 1 and 2 are of course shown considerably enlarged; in practice they would be about Va in. or A in. square.

FIGS. 3 and 4 show a teleprinter embodying a plurality of devices as shown in FIG. 1. A circular drum 1 carries a number of printing matrices on its outer surface and which are arranged in longitudinal lines parallel to its axis. Matrices arranged on any one longitudinal line bear the same prefix, e.g., 1M1, 1M2, lM3-1M64 as shown in FIG. 3. As will be apparent later it is convenient, though not necessary, that the number of matrices in a line equals 2n where n is a whole number. In the embodiment shown there are [lines of matrices, matrices in successive lines bearing increasing prefixes up to 64, i.e., the 64th line of matrices bears references 64M1, 64M2-64M64. Each line of matrices has associated with it, in a manner which will be explained later herein, a number of photosensitive diodes which, as shown in FIG. 3, are also arranged in longitudinal lines on the surface of the drum 1. Associated lines of matrices and diodes bear the same prefix, e.g., diodes associated with the matrices 1M1, lM2-1M64 are referenced lDll, lDi, lD2-1D14. The drum 1 is rotated by a motor shown purely schematically at M in FIG. 3. The number of lines of matrices and associated diodes is, in the embodiment described though not necessarily of course, equal to the number of matrices in any one line. Mounted close to the part of the drum carrying the diodes lDOlDM, ZDO-ZDM, etc. are rows of light sources which may be constituted by lightemitting gallium arsenide diodes known per se, there being one light source for each associated photosensitive diode. The number of rows of light sources is equal to the number of matrices in one line and for the embodiment shown in FIGS. 3 and 4 there are 64 such rows. Only one row is shown however in FIG. 3 for reasons of clarity. Light sources in each row bear the same prefix, e.g., the row shown in FIG. 3 is referenced 1L0, lLll, lLZ-ILM. The rows of light sources are fed from a decoder D in the data output circuit of a computer but neither the decoder nor the computer form part of this invention and since they may both be of any convenient well-known form they will not be described further.

Referring now more particularly to FIG. 4, a supply of paper P passes through an adhesive-coating arrangement generally designated A which coats the paper with suitable adhesive my means of a roller R11 which presses the paper into contact with a second roller R2 which runs in adhesive G. The teleprinter drum 1 is rotated by a motor M (shown in FIG. 3 but not in FIG. d) and the paper is pressed into contact with the surfaces of the drum by a-pinch roller R3. After printing, the paper passes through a drier l-I. As shown, the drum 1 is driven in an anticlockwise direction as is indicated by the arrow and prior to printing onto the paper passing between it and the roller R3, the charged elements on the drum pickup and retain, by means of electrostatic attraction, a suitable printing material from a container. C. After the printing operation proper, any electrostatic charge remaining on the'elements of the drum is removed by a discharge roller R4 which is of course conductive and connected to earth. A single supple voltage S is connected to the drum l by means of a slip ring and brush arrangement 2. The other pole of the voltage supply is connected to the container C.

Decoded output data signals from a computer are fed to electronic circuitry contained within the drum via the photoelectric link constituted by the light sources generally designated 1L, 2L64L in FIG. 4 and photosensitive diodes which are not shown in FiG. t since-this figure shows an end view of the drum. The electronic circuitry within the drum determines which elements of the matrices are to be energized and will be described in greater detail with reference to H6. 5.

FlG. shows so far as is necessary for an understanding thereof part of the circuitry contained within the drum. More particularly FIG. 5 shows part of the circuitry associated with one longitudinal line of matrices on the drum 1 of FIGS. 3 and 4. Each longitudinal line of matrices on the drum 1 is provided with circuitry similar to that shown in FIG. 5 but for the purposes of explanation FIG. 5 shows the circuitry associated with the line whose matrices are referenced 1M1, 1M2, 1M3- --llViI5$. The drum has contained within it all the components and interconnections shown in FIG. 5 apart from the set of light sources 1L0, ELI-ELM which are separate from the drum and which are fixed. As the drum rotates, a ring counter lRC as known per se has input pulses fed to it from the photosensitive diode 1130 which gives out a pulse every time it passes under a counter light source Lil, the counter light source shown in FIG. 5 being referenced 1L6.

Output signals from the counter RRC are applied to the bases of normally cutoff charging transistors 1T1, 1T21T64 to cause them to conduct. The ring counter is arranged and adapted in well-known manner to provide an output pulse on the lead to the base of iTl when diode lDil is energized by light source llLO, an output pulse on the lead to the base of 1T2 when lDl) is energized by light source llLil on the next line (shown in FIG. 4 but not in FIG. 5 for reasons of clarity), and so on until diode M30 is energized by light source MU) whereupon the counter lRC provides an output pulse to the base of ITM. With continued rotation of the drum the diode lDt] next encounters light source lLt) once again and the counter lRC resets itself and gives an output pulse on the lead to the base of HT], thereafter repeating the cycle outline above. Thus it will be appreciated that as the drum rotates charging transistors 1T1, lT2-1T64 are made conductive in turn.

Photosensitive diodes 1B1, 1B2, lD3-IDM provide switching signals, when they are energized by their associated light sources ILl, 1L2, 1L31LM to cause the switching transistors lTEl, lTEZ, 1TE31TEM, which are normally cut off, to become conductive, thereby connecting elements El, E2, E3-El4 of each of matrices 1M1, 1M2, lM3llM64 to their associated charging transistors lTi, 1T2, iT3-lT64i. In FIG. 5 only two of the switching transistors, these referenced lTEl and lTEZ are shown for reasons of clarity, in each of the matrices 1M1, 1M21M64. As can be seen from FIG. 5 the switching transistors lTEl have their collectors connected to the elements referenced El and the switching transistors lTEZ have their collectors connected to the elements E2. The other switching transistors ITE3, 1TE4-1TEI 4, not shown in FIG. 5, have their collectors connected to the elements E3, Ed-EM, respectively (also not shown in FIG. 5) in the matrices 1M1, 1M21M64, whilst their emitters are connected to their respective charging transistors lTl, lTZ- 1T64 as are the emitters of the switching transistors I'IEl and ITEZ shown in FIG. 5. As will now be appreciated each matrix 1M1, IMZ-llMM has a charging transistor 1T1, 1T2- 1T6d respectively associated with it and also switching transistors lTEl, 1TE llTE-for elements El, E2-EM respectively in each matrix. The collectors of the charging transistors lTl, llT2lT64 are connected to a source of supply potential S which is derived from the slip ring connec tion 2 already described with reference to FIG. 4.

As already mentioned, the circuitry shown in FIG. 5 is provided for one longitudinal line of matrices 1M1, lM2-1MM. The other lines of matrices 2M1-2M64i, 3Ml-3M64, and so on up to the line biMl-64M64, are each provided with similar circuitry to that shown in H6. 5. For example, the line of matrices references ddMl, MMZ-MAM is provided with a set of photosensitive diodes MDlL-MDM, a ring counter MRC, charging transistors MTL-MTM and 64 sets of switching transistors 64TE164TEM.

The operation of a printer in accordance with the invention will now be described with reference to FIGS. 3, 4i and 5. All the light sources 1L0, 2L0, 3L0-64L0 are normally always alight. As the drum ll rotates the photosensitive diodes IDO- --1Dll4 pass under the light sources llLO lLM and give out pulses in accordance with the light sources which are alight at the time. As mentioned before the decoder D is adapted and arranged in accordance with data fed thereto to light up the appropriate light sources at any instant. The output pulse from 1D0 causes the ring counter lRC to make charging transistor lTl conductive. Simultaneously, output pulses from the appropriate combination of diodes llDl1ll) 14 (in accordance with the character or pattern to be printed) make conductive the corresponding combination of switching transistors lTEl- -1TEM so that charging current can pass from the source S via 1T1 through the conductive combination of switching transistors to the desired combination of elements E1-EM in the matrix 1M1 to charge them up electrostatically. Identical combinations of switching transistors associated with the other matrices IMZ-ilid will also be made conductive of course at the same time, but no charging current flows through these combinations because their associated charging transistors 1T2-1T64 are not conductive. As the drum l continued to rotate output from the diodes lD0-1Dl4 will cease and the conductive transistors will cut off to prevent the electrostatic charge on the desired combination of elements from leaking away. With further rotation the diodes lDO-lDM pass under light sources 2Lil2Ll4 the output pulse from 1D@ causing the ring counter IRC to make charging transistor 1T2 conductive. Simultaneous output pulses from a combination of diodes lDl--KD14 which are energized by a desired combination of lit-up light sources 2L12L14 switch on a corresponding combination of switching transistors lTEl- 1TE14 so that the desired combination of elements E1- -Eli in the matrix 1M2 can charge up from the source S via charging transistor 1T2. Continued rotation of the drum 1 causes successive charging transistors 1T3, 1T4-1T64 to be made conductive in turn whereby an appropriate combination of elements in matrices 1M3, 1M4-1M64 may be charged up in turn, until finally desired combinations of elements in the whole line of matrices lMl-IMM is appropriately charged electrostatically after passing the final line of light sources 641.. After further rotation of the drum charged elements in the line of matrices electrostatically pick up and retain printing powder from the container C and are subsequently, with further rotation of the drum, pressed into contact with th paper by means of the pinch roller R3 to transfer the powde to the paper. As already described with reference to FIG. 4 the charged elements on the drum are discharged after printing by means of discharge roller R4 prior to the next charging and printing operation. 1

Although the operation of a printer in accordance with the invention has been described with reference to only on one line longitudinal matrices on the drum, desired combinations of elements in the matrices on the other lines are of course selected and charged up in a manner similar to that already described in detail herein.

Selection and charging of described combinations of elements in a subsequent line of matrices starts as soon as the photosensitive diodes associated with that line are energiz d by the first line of light sources, i.e., that referenced 11. 0- -1Ll4. For example, selection and charging elements in e line of matrices 2M1, 2M2-2M64 starts when the photose sitive diodes in the line 2B0, 2D1' 2D14'are energized by l1tup light sources 1L0, lLl-lLl4. Thus the combination bf desired elements in the first matrix 2M1 of the second line f matrices is selected and charged up at the same time as the desired combination of elements in thesecond matrix, 1M of the first line of matrices is selected and charged. Similarly, a desired combination of elements in the first matrix 64M] of the 64th line of matrices is selected and charged at the same time as a desired combination of elements in the last matrix 1M64 of the first line of matrices is selected and charged.

Clearly in order that elements in the lines of matrices are selected and charged in the desired manner it is necessary to provide means for synchronizing the decoder output with the rotation of the drum. Such synchronizing means are well known per se and may take a variety of forms but none is illustrated in the FIGS. for reasons ofclarity. One such form of synchronizing means may include a disc having suitably positioned opaque and transparent areas and which is fixed to the shaft driving the drum so that it rotates with the latter. Appropriately positioned photocells illuminated by suitable light sources shining through the transparent areas of the disc provide a digital output indicative of the angular position of the drum, and such output may be utilized in known manner to synchronize the output of the decoder D.

A printer in accordance with this invention is not limited of course to the use of circuitry as illustrated in FIG. 5. Variations in circuitry are possible. For example it is not essential that ring counters lRC, 2RC64RC be provided to make conductive in turn the appropriate charging transistors 1T1, ITZ-ITM as the case may be as the drum rotates. Instead it is possible to provide, for each line of matrices in the embodiment described, 64 photosensitive diodes whose outputs feed the bases of charging transistors 1T1, lT2--1T64 to make them conductive. 64 light sources fixed spirally outside the drum provide energizing input'to the appropriate photosensitive diodes as the drum rotates. Obviously in this alternative way of switching the charging transistors the photosensitive diodes lDl), 2D064D0 and their associated light sources 1L0, 2L0-64L0 are not required.

lclaim:

1. A teleprinter comprising a large number of insignia forming matrices which are carried by and insulated from a drum and which are spaced from one another along a plurality of spaced parallel lines running parallel to the drum axis; each of said matrices being composed of a plurality of mutually insulated insignia elements each of which constitutes an electrode of a condenser, said elements being in such physical relationships that different combinations of the elements of a matrix correspond to different insignia; means operable by different combinations of input electrical signals for selecting different combinations of elements of each matrix in turn in a line of matrices and charging the condensers of which these elements are electrodes; means for selecting and charging elements in one line whilst selection and charging is still being performed in a preceding line of matrices; means for applying printing material to the elements whereby those forming electrodes of charged condensers will electrostatically retain said material; and means for utilizing the elements for printing after application of the printing material thereto.

2. A teleprinter as claimed in claim 1 wherein signals for selecting elements to be charged are fed to the printer via a photoelectric link.

3. A teleprinter as claimed in claim 2 wherein the photoelectric link includes photosensitive diodes which are energized by light sources which emit light on the application of a suitable potential.

4. A printer including a plurality of lines of matrices each arranged on the surface of a cylindrical drum and parallel to the drum axis, first switch means for producing a charging path to a desired selection of electrodes which comprise elements which represent the character or pattern to be printed, second switch means operatively associated with each of said matrices and in series with said first switch means for selectively connecting a desired selection of elements in a desired matrix to one pole of a source of charging potential, the other pole of said sourcebeingconnected to a supply of printing material, means for rotating said drum, means for pressing the surface to be printed into contact with said drum, and a photoelectric link for feeding into said drum signals according to the character or characters or patterns to be printed.

5. A printer as claimed in claim 4 including means for discharging the charged elements after the printing material has been transferred to the surface to be printed.

6. A printer as claimed in claim 5 wherein said discharge means comprises a conductive roller connected to earth and adapted and arranged to contact the matrices on the drum after printing.

7. A printer as claimed in claim 4 wherein the printing material is powder as used in copying machines working on an electrostatic principle. 

1. A teleprinter comprising a large number of insignia forming matrices which are carried by and insulated from a drum and which are spaced from one another along a plurality of spaced parallel lines running parallel to the drum axis; each of said matrices being composed of a plurality of mutually insulated insignia elements each of which constitutes an electrode of a condenser, said elements being in such physical relationships that different combinations of the elements of a matrix correspond to different insignia; means operable by different combinations of input electrical signals for selecting different combinations of elements of each matrix in turn in a line of matrices and charging the condensers of which these elements are electrodes; means for selecting and charging elements in one line whilst selection and charging is still being performed in a preceding line of matrices; means for applying printing material to the elements whereby those forming electrodes of charged condensers will electrostatically retain said material; and means for utilizing the elements for printing after application of the printing material thereto.
 2. A teleprinter as claimed in claim 1 wherein signals for selecting elements to be charged are fed to the printer via a photoelectric link.
 3. A teleprinter as claimed in claim 2 wherein the photoelectric link includes photosensitive diodes which are energized by light sources which emit light on the application of a suitable potential.
 4. A printer including a plurality of lines of matrices each arranged on the surface of a cylindrical drum and parallel to the drum axis, first switch means for producing a charging path to a desired selection of electrodes which comprise elements which represent the character or pattern to be printed, second switch means operatively associated with each of said matrices and in series with said first switch means for selectively connecting a desired selection of elements in a desired matrix to one pole of a source of charging potential, the other pole of said source being connected to a supply of printing material, means for rotating said drum, means for pressing the surface to be printed into contact with said drum, and a photoelectric link for feeding into said drum signals according to the character or characters or patterns to be printed.
 5. A printer as claimed in claim 4 including means for discharging the charged elements after the printing material has been transferred to the surface to be printed.
 6. A printer as claimed in claim 5 wherein said discharge means comprises a conductive roller connected to earth and adapted and arranged to contact the matrices on the drum after printing.
 7. A printer as claimed in claim 4 wherein the printing material is powder as used in copying machines working on an electrostatic principle. 